Obsidian are great with crafting intricate and interesting stories. The sequels they have developed (KOTOR II & Fallout NV) arguably have more depth than the originals. It's a shame that their games are almost always buggy though. With a better QA team, they could shine a bit more.
In any case, them taking over DA3 was a highly unlikely rumour. It's an original Bioware IP, they're not going to let another team produce a sequel for them.